US20140003057A1 - Lighting Device - Google Patents
Lighting Device Download PDFInfo
- Publication number
- US20140003057A1 US20140003057A1 US13/832,814 US201313832814A US2014003057A1 US 20140003057 A1 US20140003057 A1 US 20140003057A1 US 201313832814 A US201313832814 A US 201313832814A US 2014003057 A1 US2014003057 A1 US 2014003057A1
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- US
- United States
- Prior art keywords
- section
- globe
- light source
- reflecting
- heat transfer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
- F21K9/20—Light sources comprising attachment means
- F21K9/23—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
- F21K9/232—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
- F21V29/50—Cooling arrangements
- F21V29/502—Cooling arrangements characterised by the adaptation for cooling of specific components
- F21V29/503—Cooling arrangements characterised by the adaptation for cooling of specific components of light sources
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
- F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
-
- F21V29/004—
-
- F21V29/22—
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
- F21V29/50—Cooling arrangements
- F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
- F21V29/50—Cooling arrangements
- F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
- F21V29/71—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V3/00—Globes; Bowls; Cover glasses
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V7/00—Reflectors for light sources
- F21V7/0008—Reflectors for light sources providing for indirect lighting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V7/00—Reflectors for light sources
- F21V7/04—Optical design
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
- F21K9/20—Light sources comprising attachment means
- F21K9/23—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
- F21K9/238—Arrangement or mounting of circuit elements integrated in the light source
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V3/00—Globes; Bowls; Cover glasses
- F21V3/04—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings
- F21V3/10—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings characterised by coatings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2115/00—Light-generating elements of semiconductor light sources
- F21Y2115/10—Light-emitting diodes [LED]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Definitions
- Embodiments described herein relate generally to a lighting device.
- Lighting devices using light emitting elements such as light emitting diodes have long lifetime and can reduce power consumption. Thus, such lighting devices are expected to replace existing incandescent bulbs.
- the problem is that the light distribution angle is narrower than that of the incandescent bulb.
- a possible solution to this problem is to expand the light distribution angle by providing a reflecting mirror inside the globe.
- FIG. 1 is a schematic partial sectional view for illustrating a lighting device according to a first embodiment
- FIGS. 2A and 2B are schematic views for illustrating a light distribution angle of the lighting device
- FIG. 3 is a schematic graph for illustrating the light distribution angle of the lighting device
- FIG. 4 is a schematic sectional view for illustrating a reflecting section having an inclined surface
- FIG. 5A is a schematic graph for illustrating a relationship between an outline dimension of a reflecting section and a light distribution angle
- FIG. 5B is a schematic graph for illustrating a relationship between a height dimension being an attachment position of the reflecting section and the light distribution angle.
- FIG. 6A is a schematic graph for illustrating a relationship between a thickness of a globe and the light distribution angle
- FIG. 6B is a schematic graph for illustrating a relationship between a height dimension of an outermost diameter portion of the globe and the light distribution angle
- FIGS. 7A and 7B are schematic partial sectional views for illustrating a lighting device according to a second embodiment
- FIGS. 8A and 8B are schematic views for illustrating heat dissipation in a lighting device
- FIGS. 9A and 9B are schematic views for illustrating a heat transfer section having an opening
- FIG. 10 is a schematic partial sectional view for illustrating an opening according to an alternative embodiment.
- FIG. 11 is a schematic sectional view for illustrating a translucent section provided in a reflecting section.
- a lighting device includes: a body section; a light source provided on one end portion of the body section and having a light emitting element; a globe provided so as to cover the light source; and a reflecting section provided opposite to the light source, a surface of the reflecting section on opposite side from the light source side being exposed from the globe.
- FIG. 1 is a schematic partial sectional view for illustrating a lighting device according to a first embodiment.
- the lighting device 1 includes a body section 2 , a light source 3 , a globe 5 , a base section 6 , a control section 7 , and a reflecting section 9 .
- the body section 2 can be shaped so that, for instance, the cross-sectional area in the direction perpendicular to the central axis 1 a gradually increases from the base section 6 side toward the globe 5 side.
- the shape is not limited thereto.
- the shape can be appropriately changed depending on e.g. the size of the light source 3 , the globe 5 , and the base section 6 .
- the shape can be made approximate to the shape of the neck portion of an incandescent bulb. This can facilitate replacement for existing incandescent bulbs.
- the body section 2 can be formed from e.g. a material having high thermal conductivity.
- the body section 2 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited to metal materials.
- the body section 2 can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin.
- a thermal emissivity of the surface of the body section 2 is preferably high.
- the thermal emissivity of the surface of the body section 2 may become higher than that of the metal surface by virtue of organic material which is included in the paint or coat.
- selective pigments ones which do not include metal fillers are more preferable.
- white paint or coat white paint of polyester resin, white paint of acryl resin, white paint of epoxy resin, white paint of silicone resin, and white paint of urethane resin which include at least one kind of white pigment can be used.
- metal oxide can be used as the white pigment.
- metal oxide one of titanium oxide (TiO2), zinc oxide (ZnO), barium sulfate (BaSO4), magnesium oxide (MgO) can be used. Two or more white paints can be appropriately mixed.
- oxidation of the metal surface is preferably used.
- an alumite treatment which forms an anodic oxidized skin layer can be used.
- the light source 3 is provided on the side provided with the globe 5 of the body section 2 .
- the radiation surface 3 a of the light source 3 is provided perpendicular to the central axis 1 a of the lighting device 1 .
- the light source 3 radiates light primarily toward the front side of the lighting device 1 .
- the light source 3 can be configured to have e.g. a plurality of light emitting elements 3 b . However, the number of light emitting elements 3 b can be appropriately changed. One or more light emitting elements 3 b can be provided depending on e.g. the purpose of the lighting device 1 and the size of the light emitting element 3 b.
- the direction of the radiation surface 3 a of the light source 3 is also not limited to that illustrated.
- the radiation surface 3 a may be provided so as to be inclined with respect to the central axis 1 a of the lighting device 1 .
- the light emitting element 3 b can be e.g. what is called a self-emitting element such as a light emitting diode, organic light emitting diode, and laser diode.
- a self-emitting element such as a light emitting diode, organic light emitting diode, and laser diode.
- a plurality of light emitting elements 3 b they can be provided in a regular arrangement pattern such as a matrix, staggered, and radial pattern, or in an arbitrary arrangement pattern.
- the globe 5 is provided on one end portion 2 a of the body section 2 so as to cover the light source 3 .
- the globe 5 can be configured to have a shape protruding to the radiation direction of light.
- the globe 5 is translucent so that the light radiated from the light source 3 can be emitted out to the outside of the lighting device 1 .
- the globe 5 can be formed from a translucent material.
- the globe 5 can be formed from e.g. glass or transparent resin such as polycarbonate.
- a diffusing agent or phosphor can be applied to the inner surface of the globe 5 , or dispersed inside the globe 5 .
- the light distribution angle can be expanded depending on the thickness T1, T2 and shape of the globe 5 .
- the base section 6 is provided on the end portion 2 b on the opposite side of the body section 2 from the side provided with the globe 5 .
- the base section 6 can be configured to have a shape attachable to the socket for receiving an incandescent bulb.
- the base section 6 can be configured to have a shape similar to e.g. E26 or E17 specified by the ES standard.
- the base section 6 is not limited to the shape illustrated, but can be appropriately changed.
- the base section 6 can also be configured to have pin-shaped terminals used for a fluorescent lamp, or an L-shaped terminal used for a ceiling hook.
- the base section 6 can be formed from e.g. a conductive material such as metal.
- the portion electrically connected to the external power supply can be formed from a conductive material such as metal, and the remaining portion can be formed from e.g. resin.
- the base section 6 illustrated in FIG. 1 includes a cylindrical shell portion 6 a having a screw thread, and an eyelet portion 6 b provided on the end portion of the shell portion 6 a on the opposite side from the end portion provided on the body section 2 .
- the control section 7 described later is electrically connected to the shell portion 6 a and the eyelet portion 6 b .
- an insulating section formed from e.g. an adhesive can be provided between the body section 2 and the base section 6 .
- the control section 7 is provided in the space formed inside the body section 2 .
- an insulating section not shown, for electrical insulation can be appropriately provided between the body section 2 and the control section 7 .
- the control section 7 can be configured to have a lighting circuit for supplying electrical power to the light source 3 .
- the lighting circuit can be configured, for instance, to convert the AC 100 V commercial power to DC and to supply it to the light source 3 .
- the control section 7 can also be configured to have a dimming circuit for dimming the light source 3 .
- the dimming circuit can be configured to perform dimming for each light emitting element 3 b , or for each group of light emitting elements 3 b.
- a substrate 8 is provided between the light source 3 and the body section 2 .
- the substrate 8 can be formed from e.g. a material having high thermal conductivity.
- the substrate 8 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), iron (Fe) and an alloy thereof,
- a wiring pattern, not shown, can be formed on the surface of the substrate 8 via an insulating layer. This facilitates electrically connecting the light source 3 to the control section 7 via the wiring pattern, not shown. Furthermore, heat generated in the light source 3 can be easily dissipated to the outside through the substrate 8 and the body section 2 .
- the substrate 8 can be configured so that a wiring pattern is formed on the surface of a ceramic base material.
- the problem is that the light distribution angle is narrower than that of the incandescent bulb.
- FIGS. 2A and 2B are schematic views for illustrating the light distribution angle of the lighting device.
- FIG. 2A is a schematic view for illustrating the light distribution angle of an incandescent bulb.
- FIG. 2B is a schematic view for illustrating the light distribution angle of a lighting device provided with the light source 3 having a light emitting element 3 b.
- a filament 103 serving as a light emitter is located around the center of the globe 105 .
- the light L radiated from the filament 103 is radiated not only to the front side and lateral side of the incandescent bulb 100 but also to the rear side of the incandescent bulb 100 .
- the light source 3 having a light emitting element 3 b is provided on the end portion 2 a of the body section 2 , the light L radiated from the light source 3 is more likely to be radiated to the front side of the lighting device 101 . However, the light L is less likely to be radiated to the rear side of the lighting device 101 .
- FIG. 3 is a schematic graph for illustrating the light distribution angle of the lighting device 101 illustrated in FIG. 2B .
- the light distribution angle is approximately 120°.
- the light distribution angle can be expanded by three-dimensionally arranging a plurality of light sources 3 .
- a reflecting section 9 is provided to expand the light distribution angle.
- the heat generated in the light source 3 is dissipated to the outside through the substrate 8 and the body section 2 .
- the heat generated in the light source dissipated to the outside through the reflecting section 9 .
- the reflecting section 9 is shaped like a plate and provided opposite to the light source 3 .
- the surface on the light source 3 side of the reflecting section 9 is exposed to the inside of the globe 5 .
- the surface of the reflecting section 9 on the opposite side from the light source 3 side is exposed to the outside of the globe 5 .
- the reflecting section 9 can be configured to have e.g. a reflecting section body 9 b and a reflecting layer 9 a provided on the surface of the reflecting section body 9 b.
- the reflecting layer 9 a can be configured to have higher reflectance than the globe 5 .
- the reflecting layer 9 a thus provided is preferably such that, for instance, the reflectance to the light radiated from the light source 3 is 90% or more.
- the reflecting layer 9 a only needs to be provided at least on the surface on the light source 3 side of the reflecting section body 9 b.
- the reflecting layer 9 a may be provided on the entire surface of the reflecting section body 9 b.
- the reflecting layer 9 a can be a layer formed by applying e.g. white resin to the surface of the reflecting section body 9 b.
- the reflecting layer 9 a is not limited thereto.
- the reflecting layer 9 a can be a layer formed by coating with a metal having high reflectance such as silver and aluminum.
- the color of the resin is not limited to white, but can be appropriately changed.
- the method for forming the reflecting layer 9 a is not limited to application and coating.
- the reflecting layer 9 a may be previously formed into a film shape and bonded to the surface of the reflecting section body 9 b.
- the reflecting section body 9 b can be configured to have higher thermal conductivity than the globe 5 .
- the reflecting section body 9 b can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited to metal materials.
- the reflecting section body 9 b can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin.
- the surface on the light source 3 side of the reflecting section 9 is exposed to the inside of the globe 5 . Furthermore, a reflecting layer 9 a is provided on the surface on the light source 3 side of the reflecting section body 9 b . That is, the reflecting layer 9 a is exposed to the inside of the globe 5 and faces the light source 3 .
- the light radiated from the light source 3 and directed to the reflecting section 9 can be made directly incident on the reflecting layer 9 a.
- the light radiated from the light source 3 and directed to the reflecting section 9 can be efficiently reflected by the reflecting layer 9 a.
- the light reflected by the reflecting layer 9 a is radiated to the lateral side and the rear side of the lighting device 1 .
- the light distribution angle can be expanded.
- the heat generated in the light source 3 is transferred to the reflecting section 9 by convection and radiation.
- the reflecting section 9 is provided opposite to the light source 3 . Thus, heat transfer by radiation is efficiently performed.
- the surface of the reflecting section 9 on the opposite side from the light source 3 side is exposed to the outside of the globe 5 .
- the heat transferred to the reflecting section 9 can be efficiently dissipated to the outside.
- the reflecting section body 9 b is formed from a material having high thermal conductivity. Thus, the heat can be dissipated to the outside more efficiently.
- a surface treatment such as painting, coating, chemical treatment, which forms a surface having a high thermal emissivity can be applied to form the reflecting layer 9 a in order to improve a thermal dissipation through a thermal radiation.
- the thermal emissivity of the reflecting layer 9 a may become higher than that of the metal surface by virtue of organic material which is included in the paint or coat.
- various selective pigments ones which do not include metal fillers are more preferable.
- white paint or coat white paint of polyester resin, white paint of acryl resin, white paint of epoxy resin, white paint of silicone resin, and white paint of urethane resin which include at least one kind of white pigment can be used.
- metal oxide can be used as the white pigment.
- the metal oxide one of titanium oxide (TiO2), zinc oxide (ZnO), barium sulfate (BaSO4), magnesium oxide (MgO) can be used. Two or more white paints can be appropriately mixed.
- oxidation of the metal surface is preferably used.
- an alumite treatment which forms an anodic oxidized skin layer can be used to form the reflecting layer 9 a.
- the material of the reflecting layer 9 a it is preferable to use material having a reflectance not less than 90 percent to the light emitted from the light source 3 . Therefore, it is more preferable to use white painting or white coating which has high reflectance in a wavelength region of a visible light, and high absorbance in a wavelength region of an infrared light.
- the front surface and the rear surface of the reflecting layer 9 a may be made by different materials or by different treatment from each other.
- the front surface (the surface facing the light source 3 ) of the reflecting layer 9 a may have a high reflectance in a wavelength region of a visible light
- the rear surface of the reflecting layer 9 a may have a high absorbance in a wavelength region of an infrared light.
- the methods to form the reflecting layer 9 a are not limited to the painting and coating.
- film or sheet can be used as the reflecting layer 9 a , which is bonded on the reflecting section body 9 b .
- the shape of the reflecting section 9 in the direction perpendicular to the central axis 1 a of the lighting device 1 is not particularly limited. However, the shape is preferably a shape rotationally symmetric about the central axis 1 a.
- the reflecting section 9 has a shape rotationally symmetric about the central axis 1 a , the light can be radiated symmetrically about the central axis 1 a.
- the reflecting section 9 can be shaped like a disk.
- the thickness dimension of the reflecting section 9 can be made e.g. nearly constant as illustrated in FIG. 1 .
- the thickness dimension of the reflecting section 9 is not limited thereto.
- the reflecting section can be configured to have a changing thickness dimension (e.g., to have an inclined surface).
- FIG. 4 is a schematic sectional view for illustrating a reflecting section 19 having an inclined surface.
- the reflecting section 19 has a reflecting section body 19 b and the aforementioned reflecting layer 9 a.
- An inclined surface 19 a is provided on the light source 3 side of the reflecting section body 19 b .
- the aforementioned reflecting layer 9 a is provided on the inclined surface 19 a .
- the reflecting layer 9 a may be provided on the entire surface of the reflecting section body 19 b.
- the inclined surface 19 a can be inclined in a direction made close to the light source 3 toward the center side of the reflecting section body 19 b.
- the inclined surface 19 a can be a flat surface or curved surface.
- the inclined surface 19 a is provided symmetrically about the central axis 1 a of the lighting device 1 . If the inclined surface 19 a is symmetric about the central axis 1 a of the lighting device 1 , the light can be radiated symmetrically about the central axis 1 a.
- the inclination angle of the inclined surface 19 a is not particularly limited.
- the inclination angle of the inclined surface 19 a can be appropriately changed depending on the distance between the light source 3 and the reflecting section 19 and the outline dimension of the reflecting section 19 .
- the light L radiated from the light source 3 and directed to the reflecting section 19 is reflected by the reflecting layer 9 a provided on the inclined surface 19 a and radiated to the lateral side and the rear side of the lighting device 1 .
- the inclined surface 19 a is inclined so as to be made close to the light source 3 side toward the center side of the reflecting section 19 .
- the incident light is easily radiated to the lateral side and the rear side of the lighting device 1 .
- the light distribution angle can be further expanded.
- FIG. 5A is a schematic graph for illustrating the relationship between the outline dimension W1 of the reflecting section 9 and the light distribution angle.
- the outline dimension W1 of the reflecting section 9 is the dimension of the reflecting section 9 in the direction perpendicular to the central axis 1 a of the lighting device 1 as shown in FIG. 1 .
- the outline dimension W1 of the reflecting section 9 is the diameter dimension of the disk.
- the light distribution angle can be expanded.
- the outline dimension W1 of the reflecting section 9 is excessively increased, the light radiated to the front side of the lighting device 1 may be excessively decreased.
- the outline dimension W1 of the reflecting section 9 is preferably made smaller than the outermost diameter dimension W3 of the globe 5 .
- the outline dimension W1 of the reflecting section 9 is preferably made smaller than the outline dimension W2 of the substrate 8 .
- the light is radiated easily to the front side of the lighting device 1 via the outside of the reflecting section 9 .
- FIG. 5B is a schematic graph for illustrating the relationship between the height dimension H1 being the attachment position of the reflecting section 9 and the light distribution angle.
- the height dimension H1 of the reflecting section 9 is the dimension between the end portion 2 a of the body section 2 and the surface on the light source 3 side of the reflecting section 9 as shown in FIG. 1 .
- the light distribution angle can be expanded.
- the light distribution angle can be expanded by increasing the outline dimension W1 of the reflecting section 9 or decreasing the height dimension H1 of the reflecting section 9 .
- the light distribution angle can be made nearly three times compared with that illustrated in FIG. 3 .
- FIG. 6A is a schematic graph for illustrating the relationship between the thickness of the globe 5 and the light distribution angle.
- the light distribution angle is expanded more easily when the thickness T1 on the light source 3 side of the globe 5 is made thinner than the thickness T2 on the reflecting section 9 side of the globe 5 as shown in FIG. 1 , rather than when the thickness T1 on the light source 3 side of the globe 5 and the thickness T2 on the reflecting section 9 side of the globe 5 are made equal in dimension.
- FIG. 6B is a schematic graph for illustrating the relationship between the height dimension H2 of the outermost diameter portion of the globe 5 and the light distribution angle.
- the light distribution angle can be expanded.
- the light distribution angle is expanded more easily when the outermost diameter dimension W3 of the globe 5 is made larger than the diameter dimension of the end portion 2 a of the body section 2 .
- the outline dimension of the portion of the globe 5 in contact with the end portion 2 a is made smaller than the outermost diameter dimension W3 of the globe 5 .
- the outermost diameter dimension W3 of the globe 5 in the portion provided with the groove can be made larger than the dimension of the body section 2 .
- the light distribution angle is expanded more easily by providing e.g. a groove in the outer peripheral surface of the body section 2 .
- the light distribution angle can be expanded by making the thickness T1 on the light source 3 side of the globe 5 thinner than the thickness T2 on the reflecting section 9 side of the globe 5 or increasing the height dimension H2 of the outermost diameter portion of the globe 5 .
- the light distribution angle can be made nearly three times compared with that illustrated in FIG. 3 .
- FIGS. 7A and 7B are schematic partial sectional views for illustrating a lighting device according to a second embodiment.
- FIG. 7A is a schematic partial sectional view of the lighting device 11 .
- FIG. 7B is a view taken in the direction of arrows A-A in FIG. 7A .
- the lighting device 11 includes a body section 2 , a light source 3 , a globe 5 , a base section 6 , a control section 7 , and a reflecting section 9 .
- the lighting device 11 includes a heat transfer section 29 .
- the heat generated in the light source 3 is dissipated to the outside through the substrate 8 and the body section 2 by thermal conduction.
- the heat generated in the light source 3 is dissipated to the outside through the reflecting section 9 by radiation and convection.
- the heat transfer section 29 is further provided.
- the heat transfer section 29 is provided inside the globe 5 .
- the end portion 29 a on the globe 5 side of the heat transfer section 29 is exposed from the globe 5 .
- the end portion 29 b on the body section 2 side of the heat transfer section 29 is at least partly in thermal contact with the end portion 2 a of the body section 2 .
- the end portion 29 c of the heat transfer section 29 is at least partly in thermal contact with the substrate 8 .
- the end portion 29 d of the heat transfer section 29 is at least partly in thermal contact with the radiation surface 3 a of the light source 3 .
- the end portion 29 e on the reflecting section 9 side of the heat transfer section 29 is at least partly in thermal contact with the reflecting section 9 .
- the end portion 29 b , the end portion 29 c , the end portion 29 d , and the end portion 29 e do not necessarily need to be all in thermal contact, but it is sufficient that at least one of them be in thermal contact.
- the end portion 29 e may be in thermal contact with the globe 5 without being exposed from the globe 5 .
- thermal contact means that heat is transferred between the heat transfer section 29 and the mating member by at least one of thermal conduction, convection, and radiation.
- the heat transfer section 29 may be abutted to transfer heat by thermal conduction.
- a small gap to the heat transfer section 29 may be provided to transfer heat by convection and radiation.
- the end portions 29 a - 29 e of the heat transfer section 29 may be abutted to the mating member, or may be spaced therefrom to the extent that heat can be transferred.
- the end portions 29 a - 29 e of the heat transfer section 29 are preferably abutted to the mating member.
- the thermal contact is not necessarily needed in the entire region of the end portions, but only needed in at least part of the end portions.
- At least one of the end portion 2 a of the body section 2 , the substrate 8 , and the radiation surface 3 a of the light source 3 serves as a heat dissipation surface on the end portion 2 a side of the body section 2 .
- the end portion of the heat transfer section 29 only needs to be at least partly in thermal contact with the heat dissipation surface on the end portion 2 a side of the body section 2 .
- the end portion of the heat transfer section 29 only needs to be at least partly in thermal contact with the reflecting section 9 .
- thermal contact is provided in as large a region as possible.
- a contact section including a material having high thermal conductivity can be provided between the end portion of the heat transfer section 29 and the heat dissipation surface on the end portion 2 a side of the body section 2 .
- the end portion 2 a of the body section 2 and the end portion 29 b of the heat transfer section 29 can be bonded with e.g. solder to provide a contact section.
- the substrate 8 and the end portion 29 c of the heat transfer section 29 can be bonded with e.g. solder to provide a contact section.
- the radiation surface 3 a of the light source 3 and the end portion 29 d of the heat transfer section 29 can be bonded with e.g. a high heat transfer adhesive added with ceramic filler having high thermal conductivity to provide a contact section.
- the reflecting section 9 and the end portion 29 e of the heat transfer section 29 can be bonded with e.g. solder to provide a contact section.
- a contact section including a material having high thermal conductivity can be provided between the inner surface of the globe 5 and the end portion 29 a of the heat transfer section 29 .
- the inner surface of the globe 5 and the end portion 29 a of the heat transfer section 29 can be bonded with e.g. a high heat transfer adhesive added with ceramic filler having high thermal conductivity to provide a contact section.
- the end portions 29 a - 29 e of the heat transfer section 29 may be brought into thermal contact with the mating side simply by abutment. However, if the end portions 29 a - 29 e of the heat transfer section 29 are brought into contact with the mating side via a contact section including a material having high thermal conductivity, the thermal resistance can be decreased. Thus, the heat dissipation effect can be further improved.
- the heat transfer section 29 and the reflecting section body 9 b may be integrally formed.
- the heat transfer section 29 , the reflecting section body 9 b , and the body section 2 may be integrally formed. Then, the heat dissipation effect can be further improved.
- the heat transfer section 29 can be formed from a material having high thermal conductivity.
- the heat transfer section 29 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited thereto.
- the heat transfer section 29 can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin.
- the heat transfer section 29 is simply provided inside the globe 5 , the difference between the light portion and the dark portion occurring on the globe 5 is increased. This may increase the brightness unevenness in the lighting device 11 .
- the heat transfer section 29 is configured to be able to reflect the light radiated from the light source 3 .
- the heat transfer section 29 can be configured to have higher reflectance than the globe 5 .
- the heat transfer section 29 can be configured to have a reflecting layer 30 on its surface.
- the reflecting layer 30 thus provided is preferably such that, for instance, the reflectance to the light radiated from the light source 3 is 90% or more.
- the reflecting layer 30 can be made similar to the aforementioned reflecting layer 9 a.
- the reflecting layer 30 can be a layer formed by applying e.g. white resin to the surface of the heat transfer section 29 .
- the reflecting layer 30 is not limited thereto, but can be a layer formed from a material such that the reflectance to the light radiated from the light source 3 is 90% or more.
- the reflecting layer 30 can be a layer formed by coating with a metal having high reflectance such as silver and aluminum.
- the color of the resin is not limited to white, but can be appropriately changed.
- the method for forming the reflecting layer 30 is not limited to application and coating.
- the reflecting layer 30 may also be previously formed into a film shape and bonded to the surface of the heat transfer section 29 .
- the heat transfer section 29 itself may be formed from a material having high reflectance.
- the heat transfer section 29 can be shaped like a plate.
- the heat transfer section 29 shaped like a plate facilitates integrally forming the reflecting section 9 and the heat transfer section 29 .
- the shape of the heat transfer section 29 is not limited thereto, but can be appropriately changed.
- the heat transfer section 29 can be configured to have an intersecting form of a plurality of plate-like bodies.
- the heat transfer section 39 can be configured to have a crossed form of two plate-like bodies.
- the heat transfer section 29 can be configured to have a shape rotationally symmetric about the central axis 11 a of the lighting device 11 .
- the heat transfer section 29 has a shape rotationally symmetric about the central axis 11 a of the lighting device 11 , the brightness in the respective regions defined by the heat transfer section 29 in the globe 5 can be made equivalent to each other.
- the difference between the light portion and the dark portion occurring on the globe 5 can be decreased. This can decrease the brightness unevenness in the lighting device 11 .
- FIGS. 8A and 8B are schematic views for illustrating heat dissipation in the lighting device.
- FIG. 8A is a schematic view for illustrating the temperature distribution near the end portion 2 a of the body section 2 in the case where the heat transfer section 39 is not provided.
- FIG. 83 is a schematic view for illustrating the temperature distribution near the end portion 2 a of the body section 2 in the case where the heat transfer section 39 having a crossed form of two plate-like bodies is provided.
- FIGS. 8A and 83 show the temperature distributions of the lighting device determined by simulation, with the output of the light source 3 set to approximately 5 W (watts), and the ambient temperature set to approximately 25° C.
- the temperature distribution is represented by monotone shading, with a higher temperature shaded darker and a lower temperature shaded lighter.
- the temperature in the end portion 2 a of the body section 2 can be decreased.
- the heat transfer section 39 heat can be dissipated also from the globe 5 side.
- the heat dissipation of the lighting device 11 can be improved. Accordingly, the lifetime of the lighting device 11 can be prolonged. Furthermore, the basic performance of the lighting device 11 such as higher luminous flux can be improved.
- FIGS. 9A and 9B are schematic views for illustrating a heat transfer section having an opening.
- FIG. 9A is a schematic partial sectional view for illustrating the heat transfer section having an opening.
- FIG. 9B is a schematic graph for illustrating the effect of providing an opening.
- the heat transfer section 49 includes an opening 49 a with height dimension H3.
- the heat transfer section 49 has an opening 49 a penetrating in its thickness direction.
- the light source 3 can be provided on the end portion 2 a of the body section 2 . Then, the heat transfer section 49 is provided at the position blocking the light radiated from the light source 3 .
- FIG. 9B by increasing the height dimension H3 of the opening 49 a , the light extraction efficiency can be increased.
- FIG. 93 illustrates the case of changing the height dimension H3 of the opening 49 a .
- the limit electrical power the electrical power which can be inputted to the light emitting element 3 b . Then, if the limit electrical power is decreased, the amount of light radiated from the light source 3 is decreased.
- the size of the opening 49 a can be appropriately determined by taking into consideration the characteristics of the light emitting element 3 b , the increase of light extraction efficiency achieved by providing the opening 49 a , and the decrease of heat dissipation due to the provision of the opening 49 a.
- the opening 49 a opens in the end portion on the body section 2 side of the heat transfer section 49 .
- the shape of the opening 49 a and the position for providing the opening 49 a can be appropriately changed.
- the light extraction efficiency can be increased by providing the opening 49 a at a position closer to the light source 3 .
- the opening 49 a is preferably configured so as to open in the end portion on the body section 2 side of the heat transfer section 49 .
- FIG. 10 is a schematic partial sectional view for illustrating an opening according to an alternative embodiment.
- the opening 59 a provided in the heat transfer section 59 opens in the end portion on the body section 2 side and the end portion on the globe 5 side of the heat transfer section 59 .
- the heat transfer section 59 is in contact with the substrate 8 on the center side and extends to the reflecting section 9 side.
- the heat transfer section 59 extends outward from the central axis of the lighting device along the shape of the globe 5 .
- the cross section of the heat transfer section 59 including the central axis of the lighting device is shaped like an umbrella.
- the opening 59 a opens in the end portion on the globe 5 side of the heat transfer section 59 . Then, as shown in FIG. 10 , the light L1 radiated from the light source 3 and reflected at the reflecting section 9 , and the light L2 reflected at the end surface of the lens 40 , are radiated to the rear side of the lighting device. Thus, the light extraction efficiency can be increased, and the light distribution angle can be expanded.
- This heat transfer section 59 can be entirely composed of one plate as shown in FIG. 10 .
- the left half plate-like body and the right half plate-like body may be integrally formed, and these two plate-like bodies may be linked at e.g. the position indicated by the dashed line of FIG. 10 .
- the left half plate-like body and the right half plate-like body in FIG. 10 may be composed of separate bodies and connected on the dashed line of FIG. 10 .
- another separate plate-like body (not shown) may be added. The added plate-like body is brought into thermal contact with the heat transfer section 59 on the dashed line shown in FIG. 10 , and can constitute part of the heat transfer section 59 .
- the light sources 3 can be arranged in an annular configuration. Furthermore, the light source 3 can be provided near the globe 5 .
- an optical element such as an annular lens 40 can be easily provided.
- the opening 59 a is configured to open at a position closer to the body section 2 , the light extraction efficiency can be further increased, and the light distribution angle can be further expanded.
- the opening can be configured to open in at least one of the end portion on the body section side of the heat transfer section and the end portion on the globe 5 side of the heat transfer section.
- the foregoing relates to the case of expanding the light distribution angle.
- the embodiments are applicable also to the case of adjusting the light distribution angle depending on the purpose and the like of the lighting device.
- a light distribution angle adapted to the purpose and the like of the lighting device can also be obtained by appropriately setting e.g. the inclination angle of the inclined surface 19 a of the reflecting section 19 , the outline dimension W1 of the reflecting section 9 , the attachment position (height dimension H1) of the reflecting section 9 , the thickness T1, T2 of the globe 5 , the height dimension H2 of the outermost diameter portion of the globe 5 , and the opening position of the opening 59 a of the heat transfer section 59 described above.
- a translucent section 69 can be provided in the reflecting section 9 so that light is easily radiated to the front side of the lighting device.
- FIG. 11 is a schematic sectional view for illustrating the translucent section 69 provided in the reflecting section 9 .
- the translucent section 69 is provided in a hole penetrating in the thickness direction of the reflecting section 9 .
- the translucent section 69 is formed from a translucent material.
- the translucent section 69 can be formed from e.g. the same material as the globe 5 .
- the light L3 radiated from the light source 3 and being incident on the reflecting section 9 is reflected.
- the light L4 incident on the translucent section 69 is transmitted through the translucent section 69 and radiated to the front side of the lighting device.
- light is easily radiated to the front side of the lighting device.
- the size, number, layout, shape and the like of the translucent section 69 are not particularly limited, but can be appropriately set depending on the light distribution characteristics required by the purpose and the like of the lighting device.
Abstract
According to one embodiment, a lighting device includes: a body section; a light source; a globe; and a reflecting section. The light source is provided on one end portion of the body section and has a light emitting element. The globe is provided so as to cover the light source. The reflecting section is provided opposite to the light source. A surface of the reflecting section on opposite side from the light source side is exposed from the globe.
Description
- This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2012-148047, filed on Jun. 29, 2012; the entire contents of which are incorporated herein by reference.
- Embodiments described herein relate generally to a lighting device.
- Recently, instead of incandescent bulbs (filament bulbs), there has been progress in the practical application of lighting devices in which light emitting elements such as light emitting diodes (LED), organic light emitting diodes, EL (electroluminescence) elements, and semiconductor lasers are used as light sources.
- Lighting devices using light emitting elements such as light emitting diodes have long lifetime and can reduce power consumption. Thus, such lighting devices are expected to replace existing incandescent bulbs.
- However, when a light emitting element such as a light emitting diode is used as a light source, the problem is that the light distribution angle is narrower than that of the incandescent bulb.
- A possible solution to this problem is to expand the light distribution angle by providing a reflecting mirror inside the globe.
- However, it is desirable to develop a lighting device capable of further expanding the light distribution angle.
-
FIG. 1 is a schematic partial sectional view for illustrating a lighting device according to a first embodiment; -
FIGS. 2A and 2B are schematic views for illustrating a light distribution angle of the lighting device; -
FIG. 3 is a schematic graph for illustrating the light distribution angle of the lighting device; -
FIG. 4 is a schematic sectional view for illustrating a reflecting section having an inclined surface; -
FIG. 5A is a schematic graph for illustrating a relationship between an outline dimension of a reflecting section and a light distribution angle; -
FIG. 5B is a schematic graph for illustrating a relationship between a height dimension being an attachment position of the reflecting section and the light distribution angle. -
FIG. 6A is a schematic graph for illustrating a relationship between a thickness of a globe and the light distribution angle; -
FIG. 6B is a schematic graph for illustrating a relationship between a height dimension of an outermost diameter portion of the globe and the light distribution angle; -
FIGS. 7A and 7B are schematic partial sectional views for illustrating a lighting device according to a second embodiment; -
FIGS. 8A and 8B are schematic views for illustrating heat dissipation in a lighting device; -
FIGS. 9A and 9B are schematic views for illustrating a heat transfer section having an opening; -
FIG. 10 is a schematic partial sectional view for illustrating an opening according to an alternative embodiment; and -
FIG. 11 is a schematic sectional view for illustrating a translucent section provided in a reflecting section. - In general, according to one embodiment, a lighting device includes: a body section; a light source provided on one end portion of the body section and having a light emitting element; a globe provided so as to cover the light source; and a reflecting section provided opposite to the light source, a surface of the reflecting section on opposite side from the light source side being exposed from the globe.
- Embodiments will now be illustrated with reference to the drawings. In the drawings, similar components are labeled with like reference numerals, and the detailed description thereof is omitted appropriately.
-
FIG. 1 is a schematic partial sectional view for illustrating a lighting device according to a first embodiment. - As shown in
FIG. 1 , thelighting device 1 includes abody section 2, alight source 3, aglobe 5, abase section 6, acontrol section 7, and a reflectingsection 9. - The
body section 2 can be shaped so that, for instance, the cross-sectional area in the direction perpendicular to thecentral axis 1 a gradually increases from thebase section 6 side toward theglobe 5 side. However, the shape is not limited thereto. For instance, the shape can be appropriately changed depending on e.g. the size of thelight source 3, theglobe 5, and thebase section 6. In this case, the shape can be made approximate to the shape of the neck portion of an incandescent bulb. This can facilitate replacement for existing incandescent bulbs. - The
body section 2 can be formed from e.g. a material having high thermal conductivity. Thebody section 2 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited to metal materials. Thebody section 2 can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin. - Various kinds of surface treatment, such as painting, coating, chemical treatment, can be applied to the surface of the
body section 2. In order to enhance a thermal radiation, a thermal emissivity of the surface of thebody section 2 is preferably high. In a case of painting or coating, the thermal emissivity of the surface of thebody section 2 may become higher than that of the metal surface by virtue of organic material which is included in the paint or coat. Among various selective pigments, ones which do not include metal fillers are more preferable. For example, as a white paint or coat, white paint of polyester resin, white paint of acryl resin, white paint of epoxy resin, white paint of silicone resin, and white paint of urethane resin which include at least one kind of white pigment can be used. As the white pigment, metal oxide can be used. As the metal oxide, one of titanium oxide (TiO2), zinc oxide (ZnO), barium sulfate (BaSO4), magnesium oxide (MgO) can be used. Two or more white paints can be appropriately mixed. - In a case of applying the chemical treatment, oxidation of the metal surface is preferably used. For example, an alumite treatment which forms an anodic oxidized skin layer can be used.
- The
light source 3 is provided on the side provided with theglobe 5 of thebody section 2. Theradiation surface 3 a of thelight source 3 is provided perpendicular to thecentral axis 1 a of thelighting device 1. Thelight source 3 radiates light primarily toward the front side of thelighting device 1. Thelight source 3 can be configured to have e.g. a plurality oflight emitting elements 3 b. However, the number oflight emitting elements 3 b can be appropriately changed. One or morelight emitting elements 3 b can be provided depending on e.g. the purpose of thelighting device 1 and the size of thelight emitting element 3 b. - The direction of the
radiation surface 3 a of thelight source 3 is also not limited to that illustrated. For instance, theradiation surface 3 a may be provided so as to be inclined with respect to thecentral axis 1 a of thelighting device 1. - The
light emitting element 3 b can be e.g. what is called a self-emitting element such as a light emitting diode, organic light emitting diode, and laser diode. In the case where a plurality oflight emitting elements 3 b are provided, they can be provided in a regular arrangement pattern such as a matrix, staggered, and radial pattern, or in an arbitrary arrangement pattern. - The
globe 5 is provided on oneend portion 2 a of thebody section 2 so as to cover thelight source 3. Theglobe 5 can be configured to have a shape protruding to the radiation direction of light. Theglobe 5 is translucent so that the light radiated from thelight source 3 can be emitted out to the outside of thelighting device 1. Theglobe 5 can be formed from a translucent material. For instance, theglobe 5 can be formed from e.g. glass or transparent resin such as polycarbonate. As necessary, a diffusing agent or phosphor can be applied to the inner surface of theglobe 5, or dispersed inside theglobe 5. - The light distribution angle can be expanded depending on the thickness T1, T2 and shape of the
globe 5. - The relation of the thickness T1, T2 and shape of the
globe 5 to the light distribution angle will be described later. - The
base section 6 is provided on theend portion 2 b on the opposite side of thebody section 2 from the side provided with theglobe 5. Thebase section 6 can be configured to have a shape attachable to the socket for receiving an incandescent bulb. Thebase section 6 can be configured to have a shape similar to e.g. E26 or E17 specified by the ES standard. However, thebase section 6 is not limited to the shape illustrated, but can be appropriately changed. For instance, thebase section 6 can also be configured to have pin-shaped terminals used for a fluorescent lamp, or an L-shaped terminal used for a ceiling hook. - The
base section 6 can be formed from e.g. a conductive material such as metal. Alternatively, the portion electrically connected to the external power supply can be formed from a conductive material such as metal, and the remaining portion can be formed from e.g. resin. - The
base section 6 illustrated inFIG. 1 includes acylindrical shell portion 6 a having a screw thread, and aneyelet portion 6 b provided on the end portion of theshell portion 6 a on the opposite side from the end portion provided on thebody section 2. To theshell portion 6 a and theeyelet portion 6 b, thecontrol section 7 described later is electrically connected. This enables thecontrol section 7 to be electrically connected to the external power supply, not shown, through theshell portion 6 a and theeyelet portion 6 b. Here, in the case where thebody section 2 is formed from e.g. metal, an insulating section formed from e.g. an adhesive can be provided between thebody section 2 and thebase section 6. - The
control section 7 is provided in the space formed inside thebody section 2. Here, an insulating section, not shown, for electrical insulation can be appropriately provided between thebody section 2 and thecontrol section 7. - The
control section 7 can be configured to have a lighting circuit for supplying electrical power to thelight source 3. In this case, the lighting circuit can be configured, for instance, to convert the AC 100 V commercial power to DC and to supply it to thelight source 3. Furthermore, thecontrol section 7 can also be configured to have a dimming circuit for dimming thelight source 3. Here, in the case where a plurality oflight emitting elements 3 b are provided, the dimming circuit can be configured to perform dimming for each light emittingelement 3 b, or for each group of light emittingelements 3 b. - A
substrate 8 is provided between thelight source 3 and thebody section 2. - The
substrate 8 can be formed from e.g. a material having high thermal conductivity. Thesubstrate 8 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), iron (Fe) and an alloy thereof, A wiring pattern, not shown, can be formed on the surface of thesubstrate 8 via an insulating layer. This facilitates electrically connecting thelight source 3 to thecontrol section 7 via the wiring pattern, not shown. Furthermore, heat generated in thelight source 3 can be easily dissipated to the outside through thesubstrate 8 and thebody section 2. Alternatively, thesubstrate 8 can be configured so that a wiring pattern is formed on the surface of a ceramic base material. - Here, if the
light source 3 having alight emitting element 3 b is provided on theend portion 2 a of thebody section 2, the problem is that the light distribution angle is narrower than that of the incandescent bulb. -
FIGS. 2A and 2B are schematic views for illustrating the light distribution angle of the lighting device. -
FIG. 2A is a schematic view for illustrating the light distribution angle of an incandescent bulb.FIG. 2B is a schematic view for illustrating the light distribution angle of a lighting device provided with thelight source 3 having alight emitting element 3 b. - As shown in
FIG. 2A , in the case of theincandescent bulb 100, afilament 103 serving as a light emitter is located around the center of theglobe 105. Thus, the light L radiated from thefilament 103 is radiated not only to the front side and lateral side of theincandescent bulb 100 but also to the rear side of theincandescent bulb 100. - In contrast, as shown in
FIG. 2B , if thelight source 3 having alight emitting element 3 b is provided on theend portion 2 a of thebody section 2, the light L radiated from thelight source 3 is more likely to be radiated to the front side of thelighting device 101. However, the light L is less likely to be radiated to the rear side of thelighting device 101. -
FIG. 3 is a schematic graph for illustrating the light distribution angle of thelighting device 101 illustrated inFIG. 2B . - As shown in
FIG. 3 , in the case of thelighting device 101, the light distribution angle is approximately 120°. - In this case, the light distribution angle can be expanded by three-dimensionally arranging a plurality of
light sources 3. However, it is technically difficult to three-dimensionally arrange a plurality oflight sources 3. This also incurs the increase of product cost. - Thus, in the
lighting device 1 according to this embodiment, a reflectingsection 9 is provided to expand the light distribution angle. - Furthermore, the heat generated in the
light source 3 is dissipated to the outside through thesubstrate 8 and thebody section 2. - However, in view of increasing the current inputted to the
light source 3 to further increase the luminous flux of thelighting device 1, it is desirable to improve heat dissipation. - Thus, in the
lighting device 1 according to this embodiment, the heat generated in the light source dissipated to the outside through the reflectingsection 9. - As shown in
FIG. 1 , the reflectingsection 9 is shaped like a plate and provided opposite to thelight source 3. - The surface on the
light source 3 side of the reflectingsection 9 is exposed to the inside of theglobe 5. - The surface of the reflecting
section 9 on the opposite side from thelight source 3 side is exposed to the outside of theglobe 5. - The reflecting
section 9 can be configured to have e.g. a reflectingsection body 9 b and a reflectinglayer 9 a provided on the surface of the reflectingsection body 9 b. - The reflecting
layer 9 a can be configured to have higher reflectance than theglobe 5. - The reflecting
layer 9 a thus provided is preferably such that, for instance, the reflectance to the light radiated from thelight source 3 is 90% or more. - The reflecting
layer 9 a only needs to be provided at least on the surface on thelight source 3 side of the reflectingsection body 9 b. - The reflecting
layer 9 a may be provided on the entire surface of the reflectingsection body 9 b. - The reflecting
layer 9 a can be a layer formed by applying e.g. white resin to the surface of the reflectingsection body 9 b. - However, the reflecting
layer 9 a is not limited thereto. For instance, the reflectinglayer 9 a can be a layer formed by coating with a metal having high reflectance such as silver and aluminum. Furthermore, the color of the resin is not limited to white, but can be appropriately changed. - The method for forming the reflecting
layer 9 a is not limited to application and coating. For instance, the reflectinglayer 9 a may be previously formed into a film shape and bonded to the surface of the reflectingsection body 9 b. - The reflecting
section body 9 b can be configured to have higher thermal conductivity than theglobe 5. - The reflecting
section body 9 b can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited to metal materials. The reflectingsection body 9 b can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin. - As described above, the surface on the
light source 3 side of the reflectingsection 9 is exposed to the inside of theglobe 5. Furthermore, a reflectinglayer 9 a is provided on the surface on thelight source 3 side of the reflectingsection body 9 b. That is, the reflectinglayer 9 a is exposed to the inside of theglobe 5 and faces thelight source 3. - Thus, the light radiated from the
light source 3 and directed to the reflectingsection 9 can be made directly incident on the reflectinglayer 9 a. - As a result, the light radiated from the
light source 3 and directed to the reflectingsection 9 can be efficiently reflected by the reflectinglayer 9 a. - The light reflected by the reflecting
layer 9 a is radiated to the lateral side and the rear side of thelighting device 1. Thus, the light distribution angle can be expanded. - The heat generated in the
light source 3 is transferred to the reflectingsection 9 by convection and radiation. - Here, the reflecting
section 9 is provided opposite to thelight source 3. Thus, heat transfer by radiation is efficiently performed. - Furthermore, the surface of the reflecting
section 9 on the opposite side from thelight source 3 side is exposed to the outside of theglobe 5. Thus, the heat transferred to the reflectingsection 9 can be efficiently dissipated to the outside. - Here, the reflecting
section body 9 b is formed from a material having high thermal conductivity. Thus, the heat can be dissipated to the outside more efficiently. - A surface treatment, such as painting, coating, chemical treatment, which forms a surface having a high thermal emissivity can be applied to form the reflecting
layer 9 a in order to improve a thermal dissipation through a thermal radiation. In a case of painting or coating, the thermal emissivity of the reflectinglayer 9 a may become higher than that of the metal surface by virtue of organic material which is included in the paint or coat. Among various selective pigments, ones which do not include metal fillers are more preferable. For example, as a white paint or coat, white paint of polyester resin, white paint of acryl resin, white paint of epoxy resin, white paint of silicone resin, and white paint of urethane resin which include at least one kind of white pigment can be used. As the white pigment, metal oxide can be used. As the metal oxide, one of titanium oxide (TiO2), zinc oxide (ZnO), barium sulfate (BaSO4), magnesium oxide (MgO) can be used. Two or more white paints can be appropriately mixed. - In a case of applying the chemical treatment, oxidation of the metal surface is preferably used. For example, an alumite treatment which forms an anodic oxidized skin layer can be used to form the reflecting
layer 9 a. - As the material of the reflecting
layer 9 a, it is preferable to use material having a reflectance not less than 90 percent to the light emitted from thelight source 3. Therefore, it is more preferable to use white painting or white coating which has high reflectance in a wavelength region of a visible light, and high absorbance in a wavelength region of an infrared light. - The front surface and the rear surface of the reflecting
layer 9 a may be made by different materials or by different treatment from each other. For example, the front surface (the surface facing the light source 3) of the reflectinglayer 9 a may have a high reflectance in a wavelength region of a visible light, and the rear surface of the reflectinglayer 9 a may have a high absorbance in a wavelength region of an infrared light. - The methods to form the reflecting
layer 9 a are not limited to the painting and coating. For example, film or sheet can be used as the reflectinglayer 9 a, which is bonded on the reflectingsection body 9 b. The shape of the reflectingsection 9 in the direction perpendicular to thecentral axis 1 a of the lighting device 1 (planar shape) is not particularly limited. However, the shape is preferably a shape rotationally symmetric about thecentral axis 1 a. - If the reflecting
section 9 has a shape rotationally symmetric about thecentral axis 1 a, the light can be radiated symmetrically about thecentral axis 1 a. - For instance, the reflecting
section 9 can be shaped like a disk. - The thickness dimension of the reflecting
section 9 can be made e.g. nearly constant as illustrated inFIG. 1 . - However, the thickness dimension of the reflecting
section 9 is not limited thereto. To further expand the light distribution angle, the reflecting section can be configured to have a changing thickness dimension (e.g., to have an inclined surface). -
FIG. 4 is a schematic sectional view for illustrating a reflectingsection 19 having an inclined surface. - As shown in
FIG. 4 , the reflectingsection 19 has a reflectingsection body 19 b and the aforementioned reflectinglayer 9 a. - An
inclined surface 19 a is provided on thelight source 3 side of the reflectingsection body 19 b. On theinclined surface 19 a, the aforementioned reflectinglayer 9 a is provided. Here, the reflectinglayer 9 a may be provided on the entire surface of the reflectingsection body 19 b. - The
inclined surface 19 a can be inclined in a direction made close to thelight source 3 toward the center side of the reflectingsection body 19 b. - The
inclined surface 19 a can be a flat surface or curved surface. - Preferably, the
inclined surface 19 a is provided symmetrically about thecentral axis 1 a of thelighting device 1. If theinclined surface 19 a is symmetric about thecentral axis 1 a of thelighting device 1, the light can be radiated symmetrically about thecentral axis 1 a. - The inclination angle of the
inclined surface 19 a is not particularly limited. The inclination angle of theinclined surface 19 a can be appropriately changed depending on the distance between thelight source 3 and the reflectingsection 19 and the outline dimension of the reflectingsection 19. - As shown in
FIG. 4 , the light L radiated from thelight source 3 and directed to the reflectingsection 19 is reflected by the reflectinglayer 9 a provided on theinclined surface 19 a and radiated to the lateral side and the rear side of thelighting device 1. - Here, the
inclined surface 19 a is inclined so as to be made close to thelight source 3 side toward the center side of the reflectingsection 19. Thus, the incident light is easily radiated to the lateral side and the rear side of thelighting device 1. - Thus, the light distribution angle can be further expanded.
- Next, the influence of the outline dimension W1 of the reflecting
section 9 and the attachment position of the reflectingsection 9 exerting on the light distribution angle is described. -
FIG. 5A is a schematic graph for illustrating the relationship between the outline dimension W1 of the reflectingsection 9 and the light distribution angle. - Here, the outline dimension W1 of the reflecting
section 9 is the dimension of the reflectingsection 9 in the direction perpendicular to thecentral axis 1 a of thelighting device 1 as shown inFIG. 1 . - For instance, in the case where the reflecting
section 9 is shaped like a disk, the outline dimension W1 of the reflectingsection 9 is the diameter dimension of the disk. - As shown in
FIG. 5A , if the outline dimension W1 of the reflectingsection 9 is increased, the light distribution angle can be expanded. - In this case, if the outline dimension W1 of the reflecting
section 9 is excessively increased, the light radiated to the front side of thelighting device 1 may be excessively decreased. - Thus, the outline dimension W1 of the reflecting
section 9 is preferably made smaller than the outermost diameter dimension W3 of theglobe 5. - Alternatively, the outline dimension W1 of the reflecting
section 9 is preferably made smaller than the outline dimension W2 of thesubstrate 8. - Then, the light is radiated easily to the front side of the
lighting device 1 via the outside of the reflectingsection 9. -
FIG. 5B is a schematic graph for illustrating the relationship between the height dimension H1 being the attachment position of the reflectingsection 9 and the light distribution angle. - Here, the height dimension H1 of the reflecting
section 9 is the dimension between theend portion 2 a of thebody section 2 and the surface on thelight source 3 side of the reflectingsection 9 as shown inFIG. 1 . - As shown in
FIG. 5B , if the height dimension H1 of the reflectingsection 9 is decreased, that is, if the reflectingsection 9 is made close to thelight source 3, then the light distribution angle can be expanded. - That is, as shown in
FIGS. 5A and 5B , the light distribution angle can be expanded by increasing the outline dimension W1 of the reflectingsection 9 or decreasing the height dimension H1 of the reflectingsection 9. - For instance, according to the knowledge obtained by the inventors, by appropriately setting the outline dimension W1 of the reflecting
section 9, the light distribution angle can be made nearly three times compared with that illustrated inFIG. 3 . - Next, the relation of the thickness T1, T2 and shape of the
globe 5 to the light distribution angle is described. -
FIG. 6A is a schematic graph for illustrating the relationship between the thickness of theglobe 5 and the light distribution angle. - As shown in
FIG. 6A , according to the knowledge obtained by the inventors, the light distribution angle is expanded more easily when the thickness T1 on thelight source 3 side of theglobe 5 is made thinner than the thickness T2 on the reflectingsection 9 side of theglobe 5 as shown inFIG. 1 , rather than when the thickness T1 on thelight source 3 side of theglobe 5 and the thickness T2 on the reflectingsection 9 side of theglobe 5 are made equal in dimension. -
FIG. 6B is a schematic graph for illustrating the relationship between the height dimension H2 of the outermost diameter portion of theglobe 5 and the light distribution angle. - As shown in
FIG. 6B , if the height dimension H2 of the outermost diameter portion of theglobe 5 is increased, that is, if the position of the outermost diameter portion of theglobe 5 is made far from thelight source 3, the light distribution angle can be expanded. - Furthermore, according to the knowledge obtained by the inventors, the light distribution angle is expanded more easily when the outermost diameter dimension W3 of the
globe 5 is made larger than the diameter dimension of theend portion 2 a of thebody section 2. - In the case where the outermost diameter dimension W3 of the
globe 5 is smaller than the diameter dimension of theend portion 2 a of thebody section 2, the outline dimension of the portion of theglobe 5 in contact with theend portion 2 a is made smaller than the outermost diameter dimension W3 of theglobe 5. - Also in such cases, by providing e.g. a groove in the outer peripheral surface of the
body section 2, the outermost diameter dimension W3 of theglobe 5 in the portion provided with the groove can be made larger than the dimension of thebody section 2. - Thus, in the case where the outermost diameter dimension W3 of the
globe 5 is smaller than the diameter dimension of theend portion 2 a of thebody section 2, the light distribution angle is expanded more easily by providing e.g. a groove in the outer peripheral surface of thebody section 2. - Thus, the light distribution angle can be expanded by making the thickness T1 on the
light source 3 side of theglobe 5 thinner than the thickness T2 on the reflectingsection 9 side of theglobe 5 or increasing the height dimension H2 of the outermost diameter portion of theglobe 5. - For instance, according to the knowledge obtained by the inventors, by appropriately setting the height dimension H2 of the outermost diameter portion of the
globe 5, the light distribution angle can be made nearly three times compared with that illustrated inFIG. 3 . -
FIGS. 7A and 7B are schematic partial sectional views for illustrating a lighting device according to a second embodiment. -
FIG. 7A is a schematic partial sectional view of thelighting device 11.FIG. 7B is a view taken in the direction of arrows A-A inFIG. 7A . - As shown in
FIGS. 7A and 7B , thelighting device 11 includes abody section 2, alight source 3, aglobe 5, abase section 6, acontrol section 7, and a reflectingsection 9. - Furthermore, the
lighting device 11 includes aheat transfer section 29. - As described above, the heat generated in the
light source 3 is dissipated to the outside through thesubstrate 8 and thebody section 2 by thermal conduction. - Furthermore, the heat generated in the
light source 3 is dissipated to the outside through the reflectingsection 9 by radiation and convection. - However, in view of increasing the current inputted to the
light source 3 to further increase the luminous flux of thelighting device 11, it is desirable to further improve heat dissipation. - Thus, in the
lighting device 11 according to this embodiment, theheat transfer section 29 is further provided. - As shown in
FIGS. 7A and 7B , theheat transfer section 29 is provided inside theglobe 5. - The
end portion 29 a on theglobe 5 side of theheat transfer section 29 is exposed from theglobe 5. - The
end portion 29 b on thebody section 2 side of theheat transfer section 29 is at least partly in thermal contact with theend portion 2 a of thebody section 2. - The
end portion 29 c of theheat transfer section 29 is at least partly in thermal contact with thesubstrate 8. - The
end portion 29 d of theheat transfer section 29 is at least partly in thermal contact with theradiation surface 3 a of thelight source 3. - The
end portion 29 e on the reflectingsection 9 side of theheat transfer section 29 is at least partly in thermal contact with the reflectingsection 9. - In this case, the
end portion 29 b, theend portion 29 c, theend portion 29 d, and theend portion 29 e do not necessarily need to be all in thermal contact, but it is sufficient that at least one of them be in thermal contact. - The
end portion 29 e may be in thermal contact with theglobe 5 without being exposed from theglobe 5. - However, if as many end portions as possible of the
end portion 29 b, theend portion 29 c, theend portion 29 d, and theend portion 29 e are in thermal contact, or theend portion 29 a is exposed from theglobe 5, then the heat dissipation effect can be improved. - In this specification, “thermal contact” means that heat is transferred between the
heat transfer section 29 and the mating member by at least one of thermal conduction, convection, and radiation. - For instance, the
heat transfer section 29 may be abutted to transfer heat by thermal conduction. Alternatively, a small gap to theheat transfer section 29 may be provided to transfer heat by convection and radiation. - That is, the
end portions 29 a-29 e of theheat transfer section 29 may be abutted to the mating member, or may be spaced therefrom to the extent that heat can be transferred. - In this case, by thermal conduction, the heat dissipation effect can be improved. Thus, the
end portions 29 a-29 e of theheat transfer section 29 are preferably abutted to the mating member. - The thermal contact is not necessarily needed in the entire region of the end portions, but only needed in at least part of the end portions.
- In this case, at least one of the
end portion 2 a of thebody section 2, thesubstrate 8, and theradiation surface 3 a of thelight source 3 serves as a heat dissipation surface on theend portion 2 a side of thebody section 2. - Thus, the end portion of the
heat transfer section 29 only needs to be at least partly in thermal contact with the heat dissipation surface on theend portion 2 a side of thebody section 2. - Furthermore, the end portion of the
heat transfer section 29 only needs to be at least partly in thermal contact with the reflectingsection 9. However, more preferably, thermal contact is provided in as large a region as possible. - A contact section including a material having high thermal conductivity can be provided between the end portion of the
heat transfer section 29 and the heat dissipation surface on theend portion 2 a side of thebody section 2. - For instance, the
end portion 2 a of thebody section 2 and theend portion 29 b of theheat transfer section 29 can be bonded with e.g. solder to provide a contact section. Furthermore, for instance, thesubstrate 8 and theend portion 29 c of theheat transfer section 29 can be bonded with e.g. solder to provide a contact section. Furthermore, for instance, theradiation surface 3 a of thelight source 3 and theend portion 29 d of theheat transfer section 29 can be bonded with e.g. a high heat transfer adhesive added with ceramic filler having high thermal conductivity to provide a contact section. Furthermore, for instance, the reflectingsection 9 and theend portion 29 e of theheat transfer section 29 can be bonded with e.g. solder to provide a contact section. - In the case where the
end portion 29 a of theheat transfer section 29 is not exposed from theglobe 5, a contact section including a material having high thermal conductivity can be provided between the inner surface of theglobe 5 and theend portion 29 a of theheat transfer section 29. - For instance, the inner surface of the
globe 5 and theend portion 29 a of theheat transfer section 29 can be bonded with e.g. a high heat transfer adhesive added with ceramic filler having high thermal conductivity to provide a contact section. - The
end portions 29 a-29 e of theheat transfer section 29 may be brought into thermal contact with the mating side simply by abutment. However, if theend portions 29 a-29 e of theheat transfer section 29 are brought into contact with the mating side via a contact section including a material having high thermal conductivity, the thermal resistance can be decreased. Thus, the heat dissipation effect can be further improved. - Furthermore, the
heat transfer section 29 and the reflectingsection body 9 b may be integrally formed. Alternatively, theheat transfer section 29, the reflectingsection body 9 b, and thebody section 2 may be integrally formed. Then, the heat dissipation effect can be further improved. - The
heat transfer section 29 can be formed from a material having high thermal conductivity. Theheat transfer section 29 can be formed from e.g. a metal material such as aluminum (Al), copper (Cu), and magnesium alloy. However, the material is not limited thereto. Theheat transfer section 29 can also be formed from e.g. an inorganic material such as aluminum nitride (AlN), or an organic material such as high thermal conductivity resin. - Here, if the
heat transfer section 29 is simply provided inside theglobe 5, the difference between the light portion and the dark portion occurring on theglobe 5 is increased. This may increase the brightness unevenness in thelighting device 11. - Thus, the
heat transfer section 29 is configured to be able to reflect the light radiated from thelight source 3. - In this case, for instance, the
heat transfer section 29 can be configured to have higher reflectance than theglobe 5. - For instance, the
heat transfer section 29 can be configured to have a reflectinglayer 30 on its surface. - The reflecting
layer 30 thus provided is preferably such that, for instance, the reflectance to the light radiated from thelight source 3 is 90% or more. - In this case, the reflecting
layer 30 can be made similar to the aforementioned reflectinglayer 9 a. - The reflecting
layer 30 can be a layer formed by applying e.g. white resin to the surface of theheat transfer section 29. - However, the reflecting
layer 30 is not limited thereto, but can be a layer formed from a material such that the reflectance to the light radiated from thelight source 3 is 90% or more. For instance, the reflectinglayer 30 can be a layer formed by coating with a metal having high reflectance such as silver and aluminum. Furthermore, the color of the resin is not limited to white, but can be appropriately changed. The method for forming the reflectinglayer 30 is not limited to application and coating. For instance, the reflectinglayer 30 may also be previously formed into a film shape and bonded to the surface of theheat transfer section 29. - Here, the
heat transfer section 29 itself may be formed from a material having high reflectance. - As illustrated in
FIG. 7B , theheat transfer section 29 can be shaped like a plate. - The
heat transfer section 29 shaped like a plate facilitates integrally forming the reflectingsection 9 and theheat transfer section 29. - However, the shape of the
heat transfer section 29 is not limited thereto, but can be appropriately changed. - For instance, the
heat transfer section 29 can be configured to have an intersecting form of a plurality of plate-like bodies. For instance, as illustrated inFIG. 83 , theheat transfer section 39 can be configured to have a crossed form of two plate-like bodies. - Furthermore, the
heat transfer section 29 can be configured to have a shape rotationally symmetric about thecentral axis 11 a of thelighting device 11. - If the
heat transfer section 29 has a shape rotationally symmetric about thecentral axis 11 a of thelighting device 11, the brightness in the respective regions defined by theheat transfer section 29 in theglobe 5 can be made equivalent to each other. - Thus, the difference between the light portion and the dark portion occurring on the
globe 5 can be decreased. This can decrease the brightness unevenness in thelighting device 11. -
FIGS. 8A and 8B are schematic views for illustrating heat dissipation in the lighting device. -
FIG. 8A is a schematic view for illustrating the temperature distribution near theend portion 2 a of thebody section 2 in the case where theheat transfer section 39 is not provided.FIG. 83 is a schematic view for illustrating the temperature distribution near theend portion 2 a of thebody section 2 in the case where theheat transfer section 39 having a crossed form of two plate-like bodies is provided. -
FIGS. 8A and 83 show the temperature distributions of the lighting device determined by simulation, with the output of thelight source 3 set to approximately 5 W (watts), and the ambient temperature set to approximately 25° C. - In
FIGS. 8A and 8B , the temperature distribution is represented by monotone shading, with a higher temperature shaded darker and a lower temperature shaded lighter. - As shown in
FIG. 8A , in the case where theheat transfer section 39 is not provided, the temperature near theend portion 2 a of thebody section 2 is increased. - On the other hand, in the case where the
heat transfer section 39 is provided, as shown inFIG. 83 , the temperature in theend portion 2 a of thebody section 2 can be decreased. - That is, if the
heat transfer section 39 is provided, heat can be dissipated also from theglobe 5 side. Thus, the heat dissipation of thelighting device 11 can be improved. Accordingly, the lifetime of thelighting device 11 can be prolonged. Furthermore, the basic performance of thelighting device 11 such as higher luminous flux can be improved. -
FIGS. 9A and 9B are schematic views for illustrating a heat transfer section having an opening. -
FIG. 9A is a schematic partial sectional view for illustrating the heat transfer section having an opening.FIG. 9B is a schematic graph for illustrating the effect of providing an opening. - As shown in
FIG. 9A , theheat transfer section 49 includes anopening 49 a with height dimension H3. - The
heat transfer section 49 has anopening 49 a penetrating in its thickness direction. - Here, for instance, as in the example illustrated in
FIGS. 7A and 73 , thelight source 3 can be provided on theend portion 2 a of thebody section 2. Then, theheat transfer section 49 is provided at the position blocking the light radiated from thelight source 3. - In this case, by providing an
opening 49 a, blocking of the light radiated from thelight source 3 can be suppressed. - For instance, as shown in
FIG. 9B , by increasing the height dimension H3 of the opening 49 a, the light extraction efficiency can be increased. Here,FIG. 93 illustrates the case of changing the height dimension H3 of the opening 49 a. However, the same applies to the case of changing the width dimension W4 of the opening 49 a. That is, also by increasing the width dimension W4 of the opening 49 a, the light extraction efficiency can be increased. - However, if an excessively
large opening 49 a is provided, then the amount of heat transfer by theheat transfer section 49, and hence the amount of heat dissipation, may be decreased. - In this case, if the height dimension H3 of the opening 49 a is increased, the amount of heat dissipation by the
heat transfer section 49 is decreased. This decreases the limit electrical power (the electrical power which can be inputted to thelight emitting element 3 b). Then, if the limit electrical power is decreased, the amount of light radiated from thelight source 3 is decreased. - Thus, the size of the opening 49 a can be appropriately determined by taking into consideration the characteristics of the
light emitting element 3 b, the increase of light extraction efficiency achieved by providing theopening 49 a, and the decrease of heat dissipation due to the provision of the opening 49 a. - In the example illustrated in
FIG. 9A , the opening 49 a opens in the end portion on thebody section 2 side of theheat transfer section 49. However, the shape of the opening 49 a and the position for providing theopening 49 a can be appropriately changed. - However, the light extraction efficiency can be increased by providing the
opening 49 a at a position closer to thelight source 3. Thus, as illustrated inFIG. 9A , the opening 49 a is preferably configured so as to open in the end portion on thebody section 2 side of theheat transfer section 49. -
FIG. 10 is a schematic partial sectional view for illustrating an opening according to an alternative embodiment. - As shown in
FIG. 10 , the opening 59 a provided in the heat transfer section 59 opens in the end portion on thebody section 2 side and the end portion on theglobe 5 side of the heat transfer section 59. The heat transfer section 59 is in contact with thesubstrate 8 on the center side and extends to the reflectingsection 9 side. The heat transfer section 59 extends outward from the central axis of the lighting device along the shape of theglobe 5. The cross section of the heat transfer section 59 including the central axis of the lighting device is shaped like an umbrella. - Here, the propagation and reflection in the
globe 5 of part of the light radiated from thelight source 3 are projected on the cross section ofFIG. 10 and represented by dot-dashed lines (light L1, L2). - In this case, the opening 59 a opens in the end portion on the
globe 5 side of the heat transfer section 59. Then, as shown inFIG. 10 , the light L1 radiated from thelight source 3 and reflected at the reflectingsection 9, and the light L2 reflected at the end surface of thelens 40, are radiated to the rear side of the lighting device. Thus, the light extraction efficiency can be increased, and the light distribution angle can be expanded. - This heat transfer section 59 can be entirely composed of one plate as shown in
FIG. 10 . Alternatively, the left half plate-like body and the right half plate-like body may be integrally formed, and these two plate-like bodies may be linked at e.g. the position indicated by the dashed line ofFIG. 10 . - Alternatively, in the heat transfer section 59, the left half plate-like body and the right half plate-like body in
FIG. 10 may be composed of separate bodies and connected on the dashed line ofFIG. 10 . To the heat transfer section 59, another separate plate-like body (not shown) may be added. The added plate-like body is brought into thermal contact with the heat transfer section 59 on the dashed line shown inFIG. 10 , and can constitute part of the heat transfer section 59. - Furthermore, if the heat transfer section 59 is shaped like an umbrella, the
light sources 3 can be arranged in an annular configuration. Furthermore, thelight source 3 can be provided near theglobe 5. - Furthermore, as shown in
FIG. 10 , an optical element such as anannular lens 40 can be easily provided. - In this case, there is no particular limitation on the position where the opening 59 a opens in the end portion on the
globe 5 side of the heat transfer section 59. - However, as shown in
FIG. 10 , if the opening 59 a is configured to open at a position closer to thebody section 2, the light extraction efficiency can be further increased, and the light distribution angle can be further expanded. - As described above, the opening can be configured to open in at least one of the end portion on the body section side of the heat transfer section and the end portion on the
globe 5 side of the heat transfer section. - The foregoing relates to the case of expanding the light distribution angle. However, the embodiments are applicable also to the case of adjusting the light distribution angle depending on the purpose and the like of the lighting device.
- For instance, a light distribution angle adapted to the purpose and the like of the lighting device can also be obtained by appropriately setting e.g. the inclination angle of the
inclined surface 19 a of the reflectingsection 19, the outline dimension W1 of the reflectingsection 9, the attachment position (height dimension H1) of the reflectingsection 9, the thickness T1, T2 of theglobe 5, the height dimension H2 of the outermost diameter portion of theglobe 5, and the opening position of the opening 59 a of the heat transfer section 59 described above. - Furthermore, depending on the purpose and the like of the lighting device, a
translucent section 69 can be provided in the reflectingsection 9 so that light is easily radiated to the front side of the lighting device. -
FIG. 11 is a schematic sectional view for illustrating thetranslucent section 69 provided in the reflectingsection 9. - The
translucent section 69 is provided in a hole penetrating in the thickness direction of the reflectingsection 9. - The
translucent section 69 is formed from a translucent material. - The
translucent section 69 can be formed from e.g. the same material as theglobe 5. - As shown in
FIG. 11 , the light L3 radiated from thelight source 3 and being incident on the reflectingsection 9 is reflected. However, the light L4 incident on thetranslucent section 69 is transmitted through thetranslucent section 69 and radiated to the front side of the lighting device. Thus, light is easily radiated to the front side of the lighting device. - In this case, the size, number, layout, shape and the like of the
translucent section 69 are not particularly limited, but can be appropriately set depending on the light distribution characteristics required by the purpose and the like of the lighting device. - While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
Claims (20)
1. A lighting device comprising:
a body section;
a light source provided on one end portion of the body section and having a light emitting element;
a globe provided so as to cover the light source; and
a reflecting section provided opposite to the light source, a surface of the reflecting section on opposite side from the light source side being exposed from the globe.
2. The device according to claim 1 , wherein a surface on the light source side of the reflecting section is exposed to inside of the globe.
3. The device according to claim 1 , wherein
the reflecting section has a reflecting section body and a reflecting layer provided at least on a surface on the light source side of the reflecting section body, and
thermal conductivity of the reflecting section body is higher than thermal conductivity of the globe.
4. The device according to claim 3 , wherein reflectance of the reflecting layer is higher than reflectance of the globe.
5. The device according to claim 3 , wherein reflectance of the reflecting layer to light radiated from the light source is 90% or more.
6. The device according to claim 3 , wherein the reflecting layer is provided on the surface on the light source side of the reflecting section body.
7. The device according to claim 3 , wherein the reflecting layer is exposed to inside of the globe and faces the light source.
8. The device according to claim 1 , wherein shape of the reflecting section in a direction perpendicular to central axis of the lighting device is rotationally symmetric about the central axis.
9. The device according to claim 3 , wherein an inclined surface is provided on the light source side of the reflecting section body.
10. The device according to claim 9 , wherein the inclined surface is inclined in a direction made close to the light source toward center side of the reflecting section body.
11. The device according to claim 9 , wherein the inclined surface is provided symmetrically about central axis of the lighting device.
12. The device according to claim 9 , wherein the reflecting layer is provided on the inclined surface.
13. The device according to claim 1 , wherein outline dimension of the reflecting section is smaller than outermost diameter dimension of the globe.
14. The device according to claim 1 , further comprising:
a substrate provided between the light source and the body section,
wherein outline dimension of the reflecting section is smaller than outline dimension of the substrate.
15. The device according to claim 1 , wherein thickness on the light source side of the globe is thinner than thickness on the reflecting section side of the globe.
16. The device according to claim 1 , wherein outermost diameter dimension of the globe is larger than diameter dimension of an end portion on the light source side of the body section.
17. The device according to claim 1 , wherein outline dimension of a portion of the globe in contact with the body section is smaller than outermost diameter dimension of the globe.
18. The device according to claim 1 , further comprising:
a heat transfer section at least partly in thermal contact with a heat dissipation surface on a side of an end portion on the light source side of the body section and at least partly in thermal contact with the reflecting section.
19. The device according to claim 18 , wherein the heat transfer section is provided inside the globe, and an end portion on the globe side of the heat transfer section is exposed from the globe.
20. The device according to claim 18 , wherein the heat transfer section reflects light radiated from the light source.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012148047A JP2014011088A (en) | 2012-06-29 | 2012-06-29 | Illumination device |
JP2012-148047 | 2012-06-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20140003057A1 true US20140003057A1 (en) | 2014-01-02 |
Family
ID=47998168
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/832,814 Abandoned US20140003057A1 (en) | 2012-06-29 | 2013-03-15 | Lighting Device |
Country Status (4)
Country | Link |
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US (1) | US20140003057A1 (en) |
EP (1) | EP2679896A1 (en) |
JP (1) | JP2014011088A (en) |
CN (1) | CN203348957U (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2919564A1 (en) * | 2014-03-14 | 2015-09-16 | Toshiba Lighting & Technology Corporation | Light emitting module substrate, light emitting module, and lighting device |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI572825B (en) | 2014-03-31 | 2017-03-01 | 瑞儀光電股份有限公司 | Lamp |
CN107091462A (en) | 2014-03-31 | 2017-08-25 | 瑞仪光电股份有限公司 | Lamp fitting |
FR3054046B1 (en) * | 2016-06-29 | 2018-08-17 | Valeo Comfort And Driving Assistance | IMAGE GENERATING DEVICE AND ASSOCIATED HIGH HEAD DISPLAY |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2460703A (en) * | 2008-06-07 | 2009-12-09 | Yu-Chen Chang | Light-transmittable cover for a light emitting diode bulb |
US8529102B2 (en) * | 2009-04-06 | 2013-09-10 | Cree, Inc. | Reflector system for lighting device |
US9052067B2 (en) * | 2010-12-22 | 2015-06-09 | Cree, Inc. | LED lamp with high color rendering index |
DE202011000929U1 (en) * | 2011-04-19 | 2011-08-11 | Jade Yang Co., Ltd. | LED lamp with reflectable lights |
CN102305363B (en) * | 2011-08-30 | 2014-09-10 | 海德信(漳州)电光源有限公司 | Large-angle omnidirectional lighting LED (light emitting diode) lamp |
-
2012
- 2012-06-29 JP JP2012148047A patent/JP2014011088A/en active Pending
-
2013
- 2013-03-15 US US13/832,814 patent/US20140003057A1/en not_active Abandoned
- 2013-03-15 EP EP13159418.6A patent/EP2679896A1/en not_active Withdrawn
- 2013-03-29 CN CN2013201506045U patent/CN203348957U/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2919564A1 (en) * | 2014-03-14 | 2015-09-16 | Toshiba Lighting & Technology Corporation | Light emitting module substrate, light emitting module, and lighting device |
Also Published As
Publication number | Publication date |
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EP2679896A1 (en) | 2014-01-01 |
CN203348957U (en) | 2013-12-18 |
JP2014011088A (en) | 2014-01-20 |
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